Question

When an ammonium salt is warmed with sodium hydroxide solution, a gas is evolved. State three ways in which you could identify this gas.

Answer 1

\[\ce{NH4Cl + NaOH -> NaCl + H2O + NH3}\]

The gas that evolved is ammonia.

Tests for Ammonia gas:

1. It has a sharp, characteristic odour.
2. It gives dense white fumes with conc. HCl.
   \[\ce{NH3 + HCl -> NH4Cl}\]
3. It gives light to deep Brown Colour or ppt. with nessler’s solution K₂HgI₄.